***************************************************************************
*                                                                         *
*                  GAP 4.6 INSTALLATION INSTRUCTIONS                      *
*                                                                         *
*************************************************************************** 

1 Installation Overview
2 Get the Archives
3 Unpacking
4 Compilation
5 Configure options
6 Test of the installation
7 Packages
8 Finish Installation and Cleanup
9 The Documentation
10 If Things Go Wrong
11 Known Problems of the Configure Process
12 Optimisation and Compiler Options
13 GAP for Mac OS X
14 Expert Windows Installation

***************************************************************************

These are the installation instructions for the traditional GAP 
distribution on UNIX (which includes the popular variant Linux), 
on Apple computers under Mac OS X, and on Windows. 

Alternative installation methods which aim to simplify the installation 
mostly by offering precompiled binaries are:
* the rsync binary distribution for Linux;
* BOB - a tool to download and build GAP and its packages from source;
* GAP installer for Windows.
They may be more suitable for many users and are explained on the GAP 
website http://www.gap-system.org.

***************************************************************************

1 Installation Overview
=======================

The "traditional" GAP distribution is designed to be installed in a similar
way on a wide range of operating systems and to allow for considerable
customisation of the installation to meet specific system needs. As a
result, it may differ from what you would expect under your particular
operating system. In particular, it does not include an automatic installer
program.

Installing the GAP distribution with all the packages and full data
libraries takes about 1.2 GB of disk space and (except on Windows) will
require a C compiler (gcc is recommended) to be installed on your system.
To get maximum benefit from GAP and from various packages it may be useful
to install a number of other free software libraries (and their associated
development tools) although they are not required for basic operation. See
http://www.gap-system.org/Download/tools.html for more details.

The installation consists of 5 easy steps:
* Get the archive suitable for your system
* Unpack the archive in the directory where you wish to install GAP
  If you are reading this file as part of a GAP installation, you have
  probably already done this.
* Compile the kernel (unless a binary has been provided already)
* Test the installation
* Compile the packages that include C code
  (some of them will only work under Unix and Mac OS X).

Installation will always install the full version of GAP. If you are
worried about losing the old version, you can keep an existing installation
of GAP in another directory, it will not be overwritten. Make sure, however,
to adjust any links or scripts so that you run the latest version.

Section "The Documentation" below contains information about the manual,
where to find and how to print it. Section "If Things Go Wrong" below lists
common problems with the installation.


2 Get the Archive
=================

You can get archives for the GAP distribution from the GAP website
http://www.gap-system.org. As different operating systems use different
archive formats, GAP is available in a variety of archives. These archives
slightly differ in the treatment of text or binary files. If you get the
wrong archive you might get error messages during compilation or not be
able to look at text files in an editor.

If you use Unix or Mac OS X, you can use the .tar.gz, .tar.bz2 or .zip
archives. If you use Windows, then use the -win.zip archive. 

You need to download the installation archive 

	gap4r6p<N>_<timestamp>
	
of the right kind, according to your operating system. The <timestamp> 
is updated whenever there is a change to the GAP system or any package.


3 Unpacking
===========

The exact method of unpacking will vary slightly, depending on the
operating system and the type of archive used.

* Unix, Mac OS X

Under Unix or Mac OS X unpack the archive gap4r6p<N>_<timestamp> 
in whatever place you want GAP to reside. 

(If you unpack the archive as root user under UNIX, make sure that you
issue the command umask 022 before, to ensure that users will have
permissions to read the files.)

* Windows

The archive must be extracted to the main directory of the C: drive. (If
you do not have permissions or sufficient free space to create directories
there, see the section "Expert Windows Installation" below).

To use the -win.zip archive you will need an appropriate extractor. Make
sure that you specify extraction to the C:\ folder (with no extra directory
name -- the directory 'gap4r6' is part of the archive) to avoid extraction
in a wrong place or in a separate directory. After extraction you can start
GAP with one of the following files:

C:\GAP4r6\bin\gap.bat
C:\GAP4r6\bin\gaprxvt.bat
C:\GAP4r6\bin\gapcmd.bat

The most highly recommended shell to run GAP is 'mintty' started using
gap.bat. It allows for convenient copying and pasting (e.g. using mouse)
and flexible customisation. Using its "Options" menu, accessible by the
right-click on the pictogram in its top left corner, you may adjust the
font and colour scheme as you prefer. Note that gap.bat will open two
windows - one actually running GAP and one auxiliary, which may be
minimised but should not be closed (otherwise your GAP session will be
terminated).


4 Compilation
=============

For the Windows version the unpacking process will already have put
binaries in place. Under Unix and Mac OS X you will have to compile such a
binary yourself. (Mac OS X users please see section "GAP for Mac OS X"
below for information about compilation)

Change to the directory 'gap4r6' (which you just created by unpacking). To
get started quickly you may simply build GAP with default settings by
issuing the two commands

./configure
make

Both will produce a lot of text output. You should end up with a shell
script bin/gap.sh(*) which you can use to start GAP. If you want, you can
copy this script later to a directory that is listed in your search path.

(* In fact, what is produced is a script called bin/gap-<configname>.sh,
where <configname> is a name which you specify or a default string, and
bin/gap.sh is a link to that script. See the section about Configure
options, below.)

Mac OS X users please note that this script must be started from within the
Terminal Application. It is not possible to start GAP by clicking this
script.

If you get strange error messages from these commands, make sure that you
got the Unix version of GAP (i.e. not the -win.zip format archive) and that
you extracted the archive on the same machine on which you compile. See
also the section "Known Problems of the Configure Process" below.


5 Configure options
===================

There are several options to the build process which you can specify at the
configure step. The following paragraphs describe these options; a brief
description of each is also available via

./configure --help

* GMP

By default, GAP 4.6 uses the external library GMP (see
http://www.gmplib.org) for large integer arithmetic, replacing the built-in
code used in previous versions and achieving a significant speed-up in
related computations. There is a version of GMP included with the GAP
archive you downloaded and this will be used unless otherwise requested.
You can configure GMP use as follows:

./configure --with-gmp=yes|no|system|"path"

If the argument you supply is yes, then the version of GMP bundled with
this GAP will be used. This is the default. If the argument is system you
are telling GAP that the GMP library is reachable with the standard search
path, under /usr or /usr/local.

You may instead give the complete path to a directory which contains the
library. If the argument is no, original GAP large integer functionality
will be used instead of GMP.

Note that --with-gmp is equivalent to --with-gmp=yes and --without-gmp is
equivalent to --with-gmp=no.

* Readline

GAP now also uses the external library Readline (see
http://www.gnu.org/software/readline) for better command-line
editing. GAP will use this library by default if it is available on
your system. You can configure Readline use as follows:

./configure --with-readline=yes|no|"path"

If the argument you supply is yes, then GAP will look in standard locations
for a Readline installed on your system. Or you can specify a path to a
Readline installation. If the supplied argument is no then readline support
will not be used.

Note that --with-readline is equivalent to --with-readline=yes and 
--without-readline is equivalent to --with-readline=no.

There is an annoying bug in the readline library on Mac OS X which makes
pasting text very slow. This can delay be ended by pressing a key (e.g.
space) during the paste, or you may prefer to build GAP without readline to
avoid this issue entirely.

* Build mode

GAP will attempt to build in 32-bit mode on 32-bit machines and in 64-bit
mode on 64-bit machines. On a 64-bit machine, you can tell GAP to build in
32-bit instead, if you wish. In that case, GMP will also be built in 32-bit
mode. You can configure the build mode as follows:

./configure ABI=32|64

The value of the argument determines the build mode GAP will attempt to
use. Note that building in 64-bit mode on a 32-bit architecture is not
supported.

It is possible (on a 64-bit machine) to have builds in both 32- and 64-bit
modes 'side by side'. To do this you could unpack your GAP archive and then
do:

./configure ABI=64
make
./configure ABI=32
make

This will create both scripts bin/gap-default32.sh and bin/gap-default64.sh
(or alternative names if you use the CONFIGNAME variable as below) and
these can be called directly to choose the version you want. The link
bin/gap.sh will point to the most recent of these.

The configure step creates the Makefile, needed for the make command. You
should not need to provide any arguments to 'make' in order to build GAP.
 
* Configuration name

In order to facilitate having several builds of GAP side-by-side, perhaps
in the case that you have both 32 and 64-bit builds or for other different
combinations of configuration options, the configure process allows you to
choose a configuration name as follows:

./configure CONFIGNAME="name"

where "name" is a string of your choice. Examples might include
"withGMP32", "withGMP64", etc., but any name which is meaningful to you is
fine. If you do not specify CONFIGNAME, then it defaults to "defaultXX"
where XX is 32 or 64, according to the (specified or detected) value of
ABI.

The configure options just described may be combined as you like or
omitted.


6 Test of the installation
==========================

You are now at a point where you can start GAP for the first time. Unix and
Mac OS X users should type

./bin/gap.sh

Windows users should start GAP with the batch file

C:\GAP4r6\bin\gap.bat

GAP should start up with its banner and after a little while give you a
command prompt 

gap>

Try a few commands to see if the compilation succeeded.

gap> 2 * 3 + 4;
10
gap> Factorial( 30 );
265252859812191058636308480000000
gap> m11 := Group((1,2,3,4,5,6,7,8,9,10,11),(3,7,11,8)(4,10,5,6));;
gap> Size( m11 );
7920
gap> Length( ConjugacyClasses( m11 ) );
10 
gap> Factors( 10^42 + 1 );
[ 29, 101, 281, 9901, 226549, 121499449, 4458192223320340849 ]

If you get the error message "hmm, I cannot find lib/init.g" you are likely
to have installed only the binary (or on Windows have not installed GAP in
the root directory of the C: drive).

If GAP starts but you get error messages for the commands you issued, the
files in the lib directory are likely to be corrupt or incomplete. Make
sure that you used the proper archive and that extraction proceeded without
errors.

Especially try the command line editing and history facilities, because
they are probably the most machine dependent feature of GAP. Enter a few
commands and then make sure that Ctrl-P redisplays the last command, that
Ctrl-E moves the cursor to the end of the line, that Ctrl-B moves the
cursor back one character, and that Ctrl-D deletes single characters. So,
after entering the above commands, typing

Ctrl-P Ctrl-E Ctrl-B Ctrl-B Ctrl-B
Ctrl-B Ctrl-D 2 Return

should give the following lines:

gap> Factors( 10^42 + 2 );
[ 2, 3, 433, 953, 128400049, 3145594690908701990242740067 ]

If you want to run a quick test of your GAP installation (though this is
not required), you can read in a test script that exercises some GAP's
capabilities. The test requires about 512 MB of memory and runs about one
minute on an Intel Core 2 Duo / 2.53 GHz machine. You will get a large
number of lines with output about the progress of the tests.

gap> Read( Filename( DirectoriesLibrary( "tst" ), "testinstall.g" ) );

test file         GAP4stones     time(msec)
-------------------------------------------
testing: ................/gap4r6/tst/zlattice.tst
zlattice.tst               0              0
testing: ................/gap4r6/tst/gaussian.tst
gaussian.tst               0             10
[ further lines deleted ]

If you want to run a more advanced check (this is not required and may take
up to an hour), you can read testall.g which is an extended test script
performing all tests from the tst directory.

gap> Read( Filename( DirectoriesLibrary( "tst" ), "testall.g" ) );

The test requires about 512 MB of memory and runs about one hour on an
Intel Core 2 Duo / 2.53 GHz machine, and produces an output similar to the
testinstall.g test.

Windows users should note that the Command Prompt user interface provided 
by Microsoft might not offer history scrolling or cut and paste with the 
mouse. To get a better environment, use scripts gap.bat or gaprxvt.bat to
start GAP instead of gapcmd.bat.


7 Packages
==========

The GAP distribution already contains all the GAP packages which we
redistribute in the gap4r6/pkg directory, and for packages that consist
only of GAP code no further installation is necessary.

Some packages however contain external binaries that will require separate
compilation. (If you use Windows you may not be able to use external
binaries anyhow, except for those packages whose binaries for Windows are 
included in their distribution, so you may skip the rest of this section.) 
You can skip this compilation now and do it later -- GAP will work fine, 
but the capabilities of the affected packages won't be available.

In general, each package contains a README file that contains information
about the package and the necessary installation. Typically the
installation for a package consists of changing to the packages directory
and issuing the commands ./configure ../..; make in the packages directory.
(This has to be done separately for every package).

If you download and run in the 'pkg' directory one of the shell scripts

    http://www.gap-system.org/Download/InstPackages.sh

for the 64-bit GAP installation or

    http://www.gap-system.org/Download/InstPackages32.sh

for the 32-bit GAP installation, it will compile most of the packages
that require compilation on UNIX systems (including Linux and Mac OS X)
with sufficiently many libraries, headers and tools available. You may 
just try to run the script or to cut and paste it line by line. If 
something doesn't work on your system, please, refer to the README file 
provided with the corresponding package. 

If you have problems with package installations please contact the package
authors as listed in the packages README file.


8 Finish Installation and Cleanup
=================================

Congratulations, your installation is finished.

Once the installation is complete, we would like to ask you to send us a
short note to support@gap-system.org, telling us about the installation.
(This is just a courtesy; we like to know how many people are using GAP and
get feedback regarding difficulties (hopefully none) that users may have
had with installation.)

We also suggest that you subscribe to our GAP Forum mailing list; see the
GAP web pages for details. Whenever there is a bug fix or new release of
GAP this is where it is announced. The GAP Forum also deals with user
questions of a general nature; bug reports and other problems you have
while installing and/or using GAP should be sent to support@gap-system.org.

If you are new to GAP, you might want to read through the following two
sections for information about the documentation.


9 The Documentation
====================

The GAP documentation is distributed in various "books". The standard
distribution contains two of them. GAP packages (see Chapter "GAP Packages"
of the GAP Reference manual and, in particular, the Section "Loading a GAP
Package") provide their own documentation in their own doc directories.

All documentation will be available automatically within every GAP session
(see Section "Help" of the GAP Tutorial and Chapter "The Help System" in
the GAP Reference manual).

There also is (if installed) an HTML version of some books that can be
viewed with an HTML browser, see Section "Changing the Help Viewer" of the
GAP Reference manual. Some of these use unicode characters for mathematical
formulae. (Firefox, Konqueror and Safari all support unicode characters.)

The manual is also available in pdf format. In the full distribution these
files are included in the directory 'gap4r6/doc' in the subdirectories
'tut' (a beginner's tutorial), 'ref' (the reference manual) and 'changes'
(changes from earlier versions).

If you want to use these manual files with the help system from your GAP
session you may check (or make sure) that your system provides some
additional software like xpdf (http://www.foolabs.com/xpdf/) or acroread
(http://www.adobe.com/products/acrobat/readstep.html).

To complete beginners, we suggest you read (parts of) the tutorial first
for an introduction to GAP 4. Then start to use the system with extensive
use of the help system (see Section "Help" of the GAP Tutorial and Chapter
"The Help System" in the GAP Reference manual).

As some of the manuals are quite large, you should not immediately print
them. If you start using GAP it can be helpful to print the tutorial (and
probably the first chapters of the reference manual). There is no
compelling reason to print the whole of the reference manual, better use
the help system which provides useful search features.


10 If Things Go Wrong
=====================

This section lists a few common problems when installing or running GAP and
their remedies. Also see the FAQ list on the GAP web pages at
http://www.gap-system.org/Faq/faq.html

* GAP starts with a warning "hmm, I cannot find `lib/init.g'"

You either started only the binary or did not edit the shell script/batch
file to give the correct library path. You must start the binary with the
command line option

-l <path>

where <path> is the path to the GAP home directory (see Section "Command
Line Options" of the GAP Reference manual).

* When starting, GAP produces error messages about undefined variables.

You might have a .gaprc file in your home directory that was intended for
GAP 4.4 but is not compatible with GAP 4.6. See section "The gap.ini and
gaprc files" in Section "Running GAP" of the GAP Reference manual.

* GAP stops with an error message "exceeded the permitted memory".

Your job required more memory than is permitted by default (this is a
safety feature to avoid single jobs wrecking a multi-user system.) You can
type return; to continue, if the error message happens repeatedly it might
be better to start the job anew and use the command line option -o to set a
higher memory limit.

* GAP stops with an error message: "cannot extend the workspace any more".

Your calculation exceeded the available memory. Most likely you asked GAP
to do something which required more memory than you have (as listing all
elements of S_15 for example). You can use the command line option -g (see
Section "Command Line Options" of the GAP Reference manual) to display how
much memory GAP uses. If this is below what your machine has available
extending the workspace is impossible. Start GAP with more memory or use
the -a option to pre-allocate initially a large piece of workspace.

* GAP is not able to allocate memory above a certain limit

In a 32-bit mode GAP is unable to use over 4 GB of memory. In fact, since 
some address space is needed for system purposes, it is likely that GAP 
sessions will be limited to 3 GB or even less.

Depending on the operating system, it also might be necessary to compile
the GAP binary statically (i.e. to include all system libraries) to avoid
collisions with system libraries located by default at an address within
the workspace. (Under Linux for example, 1 GB is a typical limit.) You can
compile a static binary using make static.

* Recompilation fails or the new binary crashes.

Call make clean and restart the configure / make process completely from
scratch. (It is possible that the operating system and/or compiler got
upgraded in the meantime and so the existing .o files cannot be used any
longer.

* A calculation runs into an error "no method found".

GAP is not able to execute a certain operation with the given arguments.
Besides the possibility of bugs in the library this means two things:
Either GAP truly is incapable of coping with this task (the objects might
be too complicated for the existing algorithms or there might be no
algorithm that can cope with the input). Another possibility is that GAP
does not know that the objects have certain nice properties (like being
finite) which are required for the available algorithms. See section
"ApplicableMethod" and "KnownPropertiesOfObject" of the GAP Reference
manual.

Problems specific to Windows

* The ^-key or "-key cannot be entered.

This is a problem if you are running a keyboard driver for some non-english
languages. These drivers catch the ^ character to produce the French
circumflex accent and do not pass it properly to GAP. No fix is known. (One
can type POW(a,b) for a^b.)

* Cut and Paste does not work

You might want to try different shells, starting each of the three .bat 
files in the 'bin' directory: gap.bat. gaprxvt.bat and gapcmd.bat. Also,
http://www.gap-system.org/Faq/faq.html#4 might give a remedy.

* GAP does not work in the remote desktop

GAP can not be started in the Windows Command Prompt shell (via gapcmd.bat)
in the remote desktop. To start GAP in the remote desktop, use scripts 
gap.bat or gaprxvt.bat which should work in such setting.

* You get an error message about the cygwin1.dll

GAP comes with a version of this dynamic library. If you have another
version installed (use "Find"), delete the older one (and probably copy the
newer one in both places).

If all these remedies fail or you encountered a bug please send a mail to
support@gap-system.org. Please give: 
* a (short, if possible) self-contained excerpt of a GAP session containing 
  both input and output that illustrates your problem (including comments 
  of why you think it is a bug); and 
* state the type of machine, operating system, (compiler used, if 
  UNIX/Linux) and version of GAP you are using (the line from the GAP 
  banner starting

GAP, Version 4.6....

when your GAP 4.6 starts up, supplies the information required).


11 Known Problems of the Configure Process
==========================================

The configure script respects compiler settings given in environment
variables. However such settings may conflict with the automatic
configuration process. If configure produces strange error messages about
not being able to run the compiler, check whether environment variables
that might affect the compilation (in particular CC, LD, CFLAGS, LDFLAGS
and C_INCLUDE_PATH) are set and reset them using unsetenv.


12 Optimization and Compiler Options
====================================

Because of the large variety of different versions of UNIX and different
compilers it is possible that the configure process will not chose best
possible optimisation level, but you might need to tell make about it.

If you want to compile GAP with further compiler options (for example
specific processor optimisations) you will have to assign them to the
variable COPTS as in the following example when calling make:

make COPTS=-option

If there are several compiler options or if they contain spaces you might
have to enclose them by quotes depending on the shell you are
using.

The configure process also introduces some default compiler options. (See
the Makefile in the bin/<architecture> directory for details.) You can
eliminate these by assigning the variable CFLAGS (which contains the
default options and COPTS) to the desired list of compiler options in the
same way as you would assign COPTS.

The recommended C compiler for GAP is the GNU C compiler gcc. The clang
compiler appears to compile GAP correctly but, just as for gcc, some 
versions have problems with the GMP library. If you cannot build GAP -
with or without GMP - using a particular compiler, you may wish to try
another compiler or different version of the same compiler.

If you do wish to use another compiler, you should run the command 'make
clean' in the GAP root directory, set the environment variable CC to
the name of your preferred compiler and then rerun configure and make. You
may have to experiment to determine the best values for CFLAGS and/or COPTS
as described above. Please let us (support@gap-system.org) know the results
of your experiments.


13 GAP for Mac OS X
===================

We hope that a binary distribution for some recent version(s) of Mac OS X
will be available shortly. In the meantime, since Mac OS X is built on top
of a variant of Unix, you should follow the Unix installations to compile
GAP; then you will be able to use all features of GAP as well as all
packages. However for installation you might need a basic knowledge of
Unix. 

The following are a couple of notes and remarks about this:

First, note that you should get the Unix type GAP archives, i.e. one of
.zip, .tar.gz or .tar.bz2 archives, but not the -win.zip archive (you won't
be able to compile the program as given in the -win.zip archive).

Next, you will need a compiler and build tools like "make". These tools are
included in the "XCode" app(lication) which is generally not installed by
default on a new Mac. You may be able to install this application by 
running an installer package already on your system (look at the Installer 
folder under Applications) but if not you can get it from Apple by 
registering as a developer (see http://developer.apple.com), or by 
downloading it from the App Store.

To compile and run GAP you will have to open the Terminal application and
type the necessary Unix commands into its window. The Terminal application
can be found in the Utilities folder in the Applications folder.
Now simply follow the Unix installation instructions to compile and start
GAP and then it will run in this Terminal window.


14 Expert Windows Installation
==============================

This section describes how to install GAP in another, non-standard
directory under Windows. This task may be slightly complicated due to
problems in the design of Windows, so if you have not edited a batch file
before you might want to contact your system administrator for help.

Alternatively, you may use one of the Windows GAP installers listed on the 
GAP website http://www.gap-system.org which will adjust all paths in batch 
files during the installation.

Whenever you use a specialised Windows installer or install GAP from 
the -win.zip archive, we recommend that you avoid paths with spaces, e.g.
'C:\My Programs\gap4r6'. If you need to install GAP on another logical 
disk, say E:, the easiest way would be just to use 'E:\gap4r6'.

If you decide to install GAP in another directory than C: from the -win.zip
archive, you will have to edit a batch file and use this file to start GAP.

First unpack the GAP distribution in the directory you want.

Lets suppose you want GAP to reside in the directory

E:\gap4r6

Extract GAP (as described in the previous section for C:) in the root
directory of the drive E: (alternatively, you can also first unpack it
elsewhere first, and then move it in the desired location.)

You now will have to edit the batch file(s) provided, which is used to
start GAP. This batch file is mainly needed so that GAP can find its
library directories, but also allows for customisation of things like
memory allocations. The file is called gap.bat and sits in the bin
directory of the GAP distribution, so that in our case it is

E:\gap4r6\bin\gap.bat

In its first line, 

set TERMINFO=/cygdrive/c/GAP4R6/terminfo

replace '/c/' by '/e/', e.g.

set TERMINFO=/cygdrive/e/GAP4R6/terminfo

Next, this file should contain the following single line

start "GAP" C:\GAP4R6\bin\mintty.exe -s 120,40 /cygdrive/c/gap4r6/bin/gapw95.exe -l /cygdrive/c/GAP4R6 %*

in which you should replace 'C:\' by 'E:\' and '/c/' by '/e/', e.g.

start "GAP" E:\GAP4R6\bin\mintty.exe -s 120,40 /cygdrive/e/gap4r6/bin/gapw95.exe -l /cygdrive/e/GAP4R6 %*

You now should be able to start GAP by clicking this gap.bat file.

If you also want to use other shells, you have to edit the gaprxvt.bat and
gapcmd.bat files in a similar way to take care of the changed path.

Please contact support@gap-system.org if you need further information.


The GAP Group, June 2012
